The code works with the version of libraries included in the book’s downloadable source code, but if you do a latest git pull of all 3 libraries you need to change the code as per the example as given in the Hasher GitHub readme

Also, the crossroads routes must be set up before the hasher.init(). Otherwize the hasher initialized callback will have no routes to execute.
Otherwise, the book is great! Bunch of people in the office want to borrow it once I am done with it:)